// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

#nullable disable

using System.Globalization;
using Microsoft.Build.Framework;

namespace Microsoft.AspNetCore.StaticWebAssets.Tasks;

public class ComputeReferenceStaticWebAssetItems : Task
{
    [Required]
    public ITaskItem[] Assets { get; set; }

    public ITaskItem[] Patterns { get; set; }

    [Required]
    public string AssetKind { get; set; }

    [Required]
    public string ProjectMode { get; set; }

    [Required]
    public string Source { get; set; }

    public bool UpdateSourceType { get; set; } = true;

    [Output]
    public ITaskItem[] StaticWebAssets { get; set; }

    [Output]
    public ITaskItem[] DiscoveryPatterns { get; set; }

    public override bool Execute()
    {
        try
        {
            var existingAssets = Assets
                .Where(asset => StaticWebAsset.HasSourceId(asset, Source))
                .Select(StaticWebAsset.FromTaskItem)
                .GroupBy(
                    a => a.ComputeTargetPath("", '/'),
                    (key, group) => (key, StaticWebAsset.ChooseNearestAssetKind(group, AssetKind)));

            var resultAssets = new List<StaticWebAsset>();
            foreach (var (key, group) in existingAssets)
            {
                if (!TryGetUniqueAsset(group, out var selected))
                {
                    if (selected == null)
                    {
                        Log.LogMessage(MessageImportance.Low, "No compatible asset found for '{0}'", key);
                        continue;
                    }
                    else
                    {
                        Log.LogError("More than one compatible asset found for '{0}'.", selected.Identity);
                        return false;
                    }
                }

                if (ShouldIncludeAssetAsReference(selected, out var reason))
                {
                    selected.SourceType = UpdateSourceType ? StaticWebAsset.SourceTypes.Project : selected.SourceType;
                    resultAssets.Add(selected);
                }
                Log.LogMessage(MessageImportance.Low, reason);
            }

            var patterns = new List<StaticWebAssetsDiscoveryPattern>();
            if (Patterns != null)
            {
                foreach (var pattern in Patterns)
                {
                    if (!StaticWebAssetsDiscoveryPattern.HasSourceId(pattern, Source))
                    {
                        Log.LogMessage(MessageImportance.Low, "Skipping pattern '{0}' because is not defined in the current project.", pattern.ItemSpec);
                    }
                    else
                    {
                        Log.LogMessage(MessageImportance.Low, "Including pattern '{0}' because is defined in the current project.", pattern.ToString());
                        patterns.Add(StaticWebAssetsDiscoveryPattern.FromTaskItem(pattern));
                    }
                }
            }

            StaticWebAssets = resultAssets.Select(a => a.ToTaskItem()).ToArray();
            DiscoveryPatterns = patterns.Select(p => p.ToTaskItem()).ToArray();
        }
        catch (Exception ex)
        {
            Log.LogErrorFromException(ex, showStackTrace: true, showDetail: true, file: null);
        }

        return !Log.HasLoggedErrors;
    }

    private static bool TryGetUniqueAsset(IEnumerable<StaticWebAsset> candidates, out StaticWebAsset selected)
    {
        selected = null;
        foreach (var asset in candidates)
        {
            if (selected != null)
            {
                return false;
            }

            selected = asset;
        }

        return selected != null;
    }

    private bool ShouldIncludeAssetAsReference(StaticWebAsset candidate, out string reason)
    {
        if (!StaticWebAssetsManifest.ManifestModes.ShouldIncludeAssetAsReference(candidate, ProjectMode))
        {
            reason = string.Format(
                CultureInfo.InvariantCulture,
                "Skipping candidate asset '{0}' because project mode is '{1}' and asset mode is '{2}'",
                candidate.Identity,
                ProjectMode,
                candidate.AssetMode);
            return false;
        }

        reason = string.Format(
            CultureInfo.InvariantCulture,
            "Accepted candidate asset '{0}' because project mode is '{1}' and asset mode is '{2}'",
            candidate.Identity,
            ProjectMode,
            candidate.AssetMode);

        return true;
    }
}
